Gardeners Question time

Miranda Janatka has kindly sent us her notes (and images) from our Gardeners Question Time meeting on Tuesday 12th June. The panel consisted of Louise, Paul and Joel from the N1 Garden Centre and Chris Preston, our own club expert. The meeting was chaired by Nancy Turnbull.

Chrysolina Americana: Rosemary Beetle

Q1. How can I get rid of Rosemary beetle?
‘Provado’ was recommended for spraying but there is no point in spraying during June and July as the bug is dormant and it is best not to spray while bees are collecting pollen. Squishing the beetles and the grubs is suggested, as well as covering the surrounding ground with a blanket and shaking the beetles off. Birds are beneficial in keeping the population of these bugs down.

Discoloured camellia leaf

Q2. What is the cause of curl and or discolouration in Camellia leaves?
If there is a low percentage of the leaves on the plant which are curled or discoloured, do not worry. As you get new growth, old leaves are shed. However if there is a high percentage of leaves with curl or discolouration it could mean that the plant is poorly fed, try feeding after flowering with ‘Miracle grow – Miracid’. Curling can suggest a dryness of the roots.

Q3. How can I get rid of snails? (in particular pepper corn sized snails)
It was suggested that these tiny snails may be water snails. Beer and yeast traps are suggested to get rid of all snails. The panel and audience discuss the benefits and problems with using nematodes. It is reminded that nematodes only work when the soil is wet but not cold and can deter preditors of the slugs and snails. (Diana Weir also sends this LINK to an article with 20 ways to combat slugs and snails).

Q4. A range of plants are all dying in one part of the garden, what could the problem be?
Due to the ongoing wet weather, fungal problems have been a much larger issue, for several reasons but in particular the rain spreads the spores. It is recommended to take affected leaves away and spray with a fungal spray.

Curling rose leaf

Q5. For the second year running, the leaves on my roses are completely curled over. What is the problem and what can I do?
The N1 experts suggested that the roses have a virus, and the best (though drastic) action would be to destroy the plants to avoid further spreading. It is possible to cut off the affected parts, but this will not cure the plant.

Q6. My Dahlias and broad beans do not grow straight, why is this?
The panel discussed whether the owner of the plants is staking them early enough or if staking actually encourages the problem. Inconsistent light and watering can cause this problem. A member of the audience suggests that planting in autumn might avoid
this problem. The panel ask if there are irregular nutrients being absorbed by the plants and over feeding is also suggested as a possible cause to the problem. It is considered that stringing up the broad beans helps and that watering the Dahlias well throughout Spring helps.

Q8. I have an infestation of mice in the polytunnel where I can strawberries. What can I do?
Nancy suggested that putting the growing fruit inside jam jars as they grow prevents mice from eating them as the mice do not entering the confined spaces. It is also recommended that if there is a bird feeder in the garden, preventing any food falling from it helps discourage unwanted pests.

Clematis with mites

Q9. My Clematis flowers half the size that it use to. The leaves are brown and crispy? What is wrong?
On observation of the underside of the leaves, the panel spots tiny mites. The use of ‘Provado’ or a soft soap is recommended.

Q10. My secateurs require sharpening, is there anywhere locally that will do this?
The KTS hardstore on Englefield Road will do this, as well as Franchi on Holloway Road. The N1 garden centre also sells an effective sharpener to keep blades sharp between times.

Q11. I am going to install some plants into a school garden. Which plants would be the most suitable for dry and shady, south west facing area.
Many plants were suggested by the panel and audience, among them: Acanthus, Olive, Spotted Laurel, Mahonia, Aucuba Rozanne and Mock Orange – Sundance. If anyone wants to donate plants to Queensbridge School, please get in touch at dbgardeners@gmail.com

Q12. I have a bald patch on my lawn under a plum tree next to the boundary of the garden. The space is 2 yards square. What can I do about it?
It was suggested that the gardener hides it. Plants such as Iberis, London Pride, Companulas, Cowslip and Primrose are also suggested but it is warned that they may spread into the lawn.

Q13. What is a ‘Chelsea Chop’ and is it a good idea?
This is a technique used (about the time of the Chelsea Flower show) in which the gardener cuts back plants to make them more stocky and to stagger growth and flowering times. It is recommended that the gardener considers carefully which plants this is suitable to attempt this with. The members of the panel from the N1 Garden Centre comment that they may cover this in more detail in their next newsletter.